Compact outdoor open-close type current transformer

Abstract

The invention discloses a compact outdoor open-close type current transformer which comprises a transformer shell formed by butt joint of an upper half housing and a lower half housing, wherein an upper half hollow framework and a lower half hollow framework are arranged in the transformer shell, an upper half iron core is arranged in the upper half hollow framework, a lower half iron core is arranged in the lower half hollow framework, and a spring jacking piece is arranged between the upper half hollow framework and the upper half iron core; a winding wire is arranged on the lower half hollow framework, a framework baffle and a sealing gasket connected to the framework baffle are arranged at the butt joint of the upper half hollow framework and the lower half hollow framework, and the framework baffle and the sealing gasket after being connected are respectively and correspondingly embedded in a guide positioning groove arranged in the upper half housing and the lower half housing; and inner spaces of the upper half housing and the lower half housing are filled with epoxy resin, a pair of lug hole plates, and a pressing plate and bolts for connecting the lug hole plates are arranged on the transformer shell. According to the invention, the fixing reliability between a cable and the transformer is improved, and screws can be prevented from falling off during high-altitude operation.

The invention claimed is: 
     
       1. A compact outdoor open-close type current transformer comprising:
 a transformer shell including a semi-annular upper half housing and a semi-annular lower half housing opposing and secured to the upper half housing, each half housing including an arcuate inner wall and an arcuate outer wall, a first space between the inner wall and the outer wall of the upper half housing defining a first semi-annular space, and a second space between the inner wall and the outer wall of the lower half housing defining a second semi-annular space, the first and second semi-annular spaces together defining an annular space formed from an annular space having a circular outer periphery and a circular inner periphery, the inner periphery having a center which is eccentric with respect to a center of the outer periphery and is located inside the upper half housing; 
 a semi-annular upper half framework disposed in the semi-annular space of the upper half housing, and a semi-annular lower half framework disposed in the semi-annular space of the lower half housing and opposing the upper half framework; 
 a semi-annular upper iron core disposed in the upper framework and a semi-annular lower iron core disposed in the lower framework and opposing the upper iron core; and 
 a winding wire wrapped around the lower framework. 
 
     
     
       2. A current transformer as claimed in  claim 1  wherein the annular space comprises an oval annular space having a first axis and a second axis shorter than the first axis and extending perpendicular to the first axis. 
     
     
       3. A current transformer as claimed in  claim 1  wherein the annular space has a circular outer periphery and a circular inner periphery, the inner periphery having a center which is eccentric with respect to a center of the outer periphery and located inside the upper half housing. 
     
     
       4. A current transformer as claimed in  claim 1  including a spring jacking piece disposed inside the upper half framework between an inner peripheral surface of the upper half framework and the upper iron core. 
     
     
       5. A current transformer as claimed in  claim 1  including a pair of lug hole plates mounted on one of the upper and lower half housings for securing a primary side cable, a pressing plate opposing the lug hole plates, and bolts connecting the pressing plate to the lug hole plates. 
     
     
       6. A current transformer as claimed in  claim 1  including an epoxy resin which fills an interior of the upper and lower half housings around the upper and lower half frameworks. 
     
     
       7. A current transformer as claimed in  claim 1  including a first fixing block mounted on an exterior of one of the upper and lower half housings, a second fixing block mounted on an exterior of the other of the upper and lower half housings opposing the first fixing block, and a screw which is rotatably mounted in a bore in the first fixing block and threadingly engaged with internal threads in the second fixing block. 
     
     
       8. A current transformer as claimed in  claim 7  wherein:
 the screw includes a bolt head, a rod section, and a threaded section having an outer diameter larger than an outer diameter of the rod section; 
 the bore in the first fixing block has a first portion which rotatably receives the rod section and a second portion which has an inner diameter larger than an inner diameter of the first portion and which houses the threaded section of the bolt; 
 the bolt head has outer dimensions larger than the inner diameter of the first portion of the bore; and 
 the outer diameter of the threaded section of the screw has is larger than the inner diameter of the first portion of the bore, whereby the screw cannot fall out of the bore in the first fixing block. 
 
     
     
       9. A current transformer as claimed in  claim 7  including an inlay nut disposed in the second fixing block and having internal threads, wherein the screw is screwed into the internal threads of the threaded insert. 
     
     
       10. A current transformer as claimed in  claim 1  including a waterproof terminal which is inserted into the lower half housing, and a lead which is connected with the winding wire and passes through the waterproof terminal. 
     
     
       11. A current transformer as claimed in  claim 1  wherein:
 the upper half housing and the lower half housing each comprise a shell seat and a shell cover secured to the shell seat; 
 an epoxy pouring hole is formed in a top surface of the each of the shell covers; and 
 each of the epoxy pouring holes is closed by a corresponding sealing cover. 
 
     
     
       12. A current transformer as claimed in  claim 5  including an arc-shaped positioning plate provided on the transformer shell between the lug hole plates.